Complete electrodynamics of a BCS superconductor with μeV energy scales: Microwave spectroscopy on titanium at mK temperatures

  title={Complete electrodynamics of a BCS superconductor with $\mu$eV energy scales: Microwave spectroscopy on titanium at mK temperatures},
  author={Markus Thiemann and Martin Dressel and Marc Scheffler},
  journal={Physical Review B},
We performed resonant microwave measurements on superconducting titanium (Ti) down to temperatures of 40~mK, well below its critical temperature $T_\mathrm{c} \approx 0.5$~K. Our wide frequency range 3.3-40~GHz contains the zero-temperature energy gap $2\Delta_0$ and allows us to probe the full electrodynamics of the superconducting state, including excitations across the gap and the low-frequency responses of superfluid condensate and thermal quasiparticles. The observed behavior follows the… Expand

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